In an automotive vehicle limited space is allotted beneath or in front of the instrument panel for the heating and air conditioning system In vehicles which have single zone systems compactly designed to fit within the allotted space it is sometimes desirable to provide a dual zone system. A dual zone system allows the driver and the passenger to have separate control of the temperature to maximize the comfort of each individual. Extending the zone system further, a separate control or controls for the rear seat region may also be desirable.
Single zone systems are generally designed to optimally utilize the amount of available space in a given type of vehicle as well as to conform to the shape of the space. When a dual zone system is designed, it generally must conform to the same size and shape, thereby requiring an additional function to be added without extra room to add it. Moreover, when a dual zone system is provided for a vehicle, is often desired to offer to customers a less expensive single zone system as well. The expense of tooling for wholly different systems can be prohibitive, however.